Hyperthyroidism

Topic Overview

What is hyperthyroidism?

Hyperthyroidism means your
thyroid makes too much thyroid hormone. Your thyroid
is a gland in the front of your neck. It controls your
metabolism, which is how your body turns food into
energy. It also affects your heart, muscles, bones, and
cholesterol.

Having too much thyroid
hormone can make a lot of things in your body speed up. You may lose weight
quickly, have a fast heartbeat, sweat a lot, or feel nervous and moody. Or you
may have no symptoms at all. While your doctor is doing a test for another reason, he or she may discover that you have
hyperthyroidism.

Hyperthyroidism is easily treated. With treatment, you can lead a healthy
life. Without treatment, hyperthyroidism can lead to serious heart problems,
bone problems, and a dangerous condition called thyroid storm.

What causes hyperthyroidism?

Graves' disease causes most hyperthyroidism. In
Graves' disease, the body's natural defense (immune) system attacks the thyroid
gland. The thyroid fights back by making too much thyroid hormone. Like many
thyroid problems, it often runs in families.

Sometimes
hyperthyroidism is caused by a swollen thyroid or small growths in the thyroid
called
thyroid nodules.

This topic focuses on
hyperthyroidism caused by Graves' disease.

What are the symptoms?

You may have no symptoms at all.
Or:

You may feel nervous, moody, weak, or
tired.

Your hands may shake, your heart may beat fast, or you may
have problems breathing.

You may be hot and sweaty or have warm, red, itchy
skin.

You may have more bowel movements than usual.

You
may have fine, soft hair that is falling out.

You may lose weight
even though you eat the same or more than usual.

If you have any of these symptoms, call your doctor.
Without treatment, hyperthyroidism can lead to heart problems, bone problems,
and a dangerous condition called thyroid storm.

How is hyperthyroidism diagnosed?

Your doctor
will ask you about your symptoms and do a physical exam. Then he or she will
order blood tests to see how much thyroid hormone your body is making.

Sometimes hyperthyroidism is found while you are having a test for
another reason. You may be surprised to find out that you have this
problem.

How is it treated?

If
your symptoms bother you, your doctor may give you pills called
beta-blockers. These can help you feel better while
you and your doctor decide what your treatment should be. Hyperthyroidism can lead
to more serious problems. So even if your symptoms
do not bother you, you still need treatment.

Radioactive iodine and antithyroid
medicine are the treatments doctors use most often. The best treatment for you
will depend on a number of things, including your age. Some people need more
than one kind of treatment.

Radioactive iodine is the most common
treatment. Most people are cured after taking one dose. It destroys part of
your thyroid gland, but it does not harm any other parts of your body.

Antithyroid medicine works best if your symptoms are mild. These
pills do not damage your thyroid gland. But they do not always work, and you
have to take them at the same time every day. If they stop working, you may
need to try radioactive iodine.

After treatment, you will need regular blood tests. These
tests check to see if your hyperthyroidism has come back. They also check to
see if you are making enough thyroid hormone. Sometimes treatment cures
hyperthyroidism but causes the opposite problem—too little thyroid hormone. If
this happens, you may need to take thyroid hormone pills for the rest of your
life.

Cause

Graves' disease
is the most common cause of
hyperthyroidism. Graves' disease causes the thyroid
gland to make too much thyroid hormone. Graves' disease, like many thyroid
problems, often runs in families.

Other common causes
include:

Thyroid nodules. Thyroid
nodules are abnormal growths in the thyroid gland that can make too much
thyroid hormone. For more information, see the topic
Thyroid Nodules.

Thyroiditis.Thyroiditis occurs when your body makes
antibodies that damage your thyroid gland. You can
also get thyroiditis from a viral or bacterial infection. At first, thyroiditis
may cause your thyroid levels to rise as hormone leaks out from the damaged
gland. Later, levels may be low (hypothyroidism)
until the gland repairs itself.

Hyperthyroidism can occur at any age but rarely affects children. It affects women more often than men. Graves' disease is the most common cause of hyperthyroidism.

Symptoms

You may have
hyperthyroidism if you:

Feel nervous, moody, weak, or
tired.

Have hand tremors, or have a fast or irregular heartbeat, or
have trouble breathing even when you are resting.

Feel very hot, sweat a lot, or
have warm, red skin that may be itchy.

Have frequent and sometimes
loose bowel movements.

Have fine, soft hair that is falling
out.

Lose weight even though you are eating normally or more than
usual.

Also, some women have irregular menstrual cycles or
stop having periods altogether. And some men may develop enlarged
breasts.

The symptoms of hyperthyroidism are not the same for
everyone. Your symptoms will depend on how much hormone your thyroid gland is
making, how long you have had the condition, and
your age. If you are older, it's easy to mistakenly
dismiss your symptoms as normal signs of aging.

Complications

Graves' ophthalmopathy is a possible complication of hyperthyroidism. It can
occur before, after, or at the same time as your symptoms of hyperthyroidism.
People with Graves' ophthalmopathy develop eye problems, including
bulging, reddened eyes, sensitivity to light, and blurring or double vision.
People who smoke are more likely to develop Graves' ophthalmopathy.

If you have Graves' ophthalmopathy, it may temporarily get worse if you
have radioactive iodine treatment. On the other hand, it may get better if you
take antithyroid medicine.

Have trouble replacing
calcium and other minerals in your bones, which can lead to
osteoporosis.

In rare cases, hyperthyroidism can cause a
life-threatening condition called
thyroid storm, which happens when the thyroid gland
releases large amounts of thyroid hormones in a short period of time.

What Happens

If your thyroid gland makes
too much
thyroid hormone, you may have symptoms of
hyperthyroidism. Most hyperthyroidism is caused by an
immune system problem called
Graves' disease. At first, your hyperthyroidism may
make you feel hot, have tremors in your hands, or lose weight. Over time, you
may notice that your heart is beating fast, that you feel anxious, or that you
are having a lot of bowel movements. You may also feel like you just don't have
as much energy as usual.

Hyperthyroidism typically does not go
away on its own. Most people need treatment to make hyperthyroidism go away.
After treatment, many people develop
hypothyroidism (too little thyroid hormone).

In rare cases, hyperthyroidism can cause a life-threatening condition
called
thyroid storm, which occurs when the thyroid gland
releases large amounts of thyroid hormones in a short period of time.

What Increases Your Risk

You are more likely to have
hyperthyroidism if:

You are female.

You have a family history of
thyroid problems. People who have close relatives with
Graves' disease or other thyroid problems are more
likely to develop hyperthyroidism.

You have an
autoimmune disease, such as
Addison's disease or
type 1 diabetes.

You smoke cigarettes.
People who smoke are more likely to have Graves' disease and are more likely to
have
Graves' ophthalmopathy.

When To Call a Doctor

The most serious problem
associated with hyperthyroidism is a life-threatening condition called
thyroid storm.

Call 911 or other emergency services immediately if you have serious signs of thyroid
storm such as
shock or
delirium.

Call your doctor immediately if you have been diagnosed with
hyperthyroidism and:

You feel very irritable.

You have
unusually high or low
blood pressure compared to your normal blood pressure.

You feel nauseated, are
throwing up, or have diarrhea.

Your heart is beating very fast or
you have chest pain.

You have a fever.

You are confused
or feel sleepy.

You cannot breathe well or you feel very tired,
which can be symptoms of
heart failure.

You
are losing weight even though you are eating normally or more than
usual.

Your throat is swollen or you are having trouble swallowing.

Watchful waiting

Watchful waiting is a period of time during
which you and your doctor observe your symptoms without using medical
treatment. If you think you have symptoms of hyperthyroidism, watchful waiting
is not a good idea. Call your doctor if you think you may have hyperthyroidism,
so you can be treated early and reduce your chances of having more serious
problems.

Who to see

Health professionals who are qualified to diagnose and treat
hyperthyroidism include:

Early detection

It is not clear whether people who do not
have any risk factors and who do not have any symptoms of hyperthyroidism need
to be tested regularly for thyroid problems. The American Thyroid Association
recommends that adults, particularly women, be screened for thyroid problems
every 5 years, beginning at age 35. The U.S. Preventive Services Task Force
does not think there is enough evidence to recommend either for or against
regular thyroid testing. Talk to your doctor about whether you need to be
tested for thyroid problems.1, 2

Treatment Overview

There are three treatments for
hyperthyroidism. Antithyroid medicine and
radioactive iodine are the ones doctors use most often. In rare cases, surgery
may be done. Hyperthyroidism can lead to more serious problems. So even if your symptoms are not bothering you, you still need
treatment.

The kind of treatment you have depends on your age, what is causing your
hyperthyroidism, how much thyroid hormone your body is making, and other
medical conditions you may have. Each kind of treatment has benefits and risks.
Discuss the benefits and risks of each kind of treatment
with your doctor. For some people, more than one kind of treatment may be
needed.

Initial treatment

Initial treatment for
hyperthyroidism usually is antithyroid medicine or
radioactive iodine therapy. If you have a lot of symptoms, your doctor may
recommend that you take antithyroid medicine first to help you feel better. Then
you can decide whether to have radioactive iodine therapy.

Antithyroid medicines work best if
you have mild hyperthyroidism, if this is the first time you are being treated
for
Graves' disease, if you are younger than 50, or if
your
thyroid gland is only swollen a little bit (small
goiter).

Radioactive iodine is often
recommended if you have Graves' disease and are older than 50, or if you have
thyroid nodules (toxic multinodular goiter) that are
releasing too much thyroid hormone. Radioactive iodine is not used if:

You
are pregnant or you want to become pregnant within 6 months of
treatment.

You are breast-feeding.

You have
thyroiditis or another kind of hyperthyroidism that is
often temporary.

If you have symptoms such as a fast heartbeat, tremors,
sweating, nervousness, or dry eyes, you may take some
additional medicines to treat those symptoms.

Surgery is not usually part of initial treatment. You may need
surgery if your thyroid gland is so big that you have a hard time swallowing or
breathing. Or you may need surgery if a single large
thyroid nodule is releasing too much thyroid hormone.

Ongoing treatment

During and after treatment for
hyperthyroidism, you will have regular blood tests to
check your levels of
thyroid-stimulating hormone (TSH). You will also have
regular
thyroid hormone tests to check your levels of
hormones called T4 and T3. These tests are a good way to know how well your treatment
is working. If your symptoms do not go away after your initial treatment, you
may need to repeat the treatment or try a different treatment.

If you have
Graves' disease and have been taking antithyroid
medicine but your hyperthyroidism has not improved, you can continue to take
antithyroid medicine or you can try
radioactive iodine therapy.

If you have
lots of side effects from antithyroid medicines and radioactive iodine is not
an option for you, you may need surgery to remove all or part of your thyroid
gland (thyroidectomy).

Sometimes treatment cures your hyperthyroidism but may
cause
hypothyroidism. Hypothyroidism is the opposite of
hyperthyroidism—instead of making too much thyroid hormone, your body is now
making too little thyroid hormone. Hypothyroidism is most common after
treatment with radioactive iodine. But it can also occur after surgery and
sometimes after taking antithyroid medicine.

Be sure to call your doctor if you start to gain weight, feel tired, or feel cold more
often than usual. These symptoms may mean you have hypothyroidism and you need
to take a different medicine called
thyroid hormone medicine. For more information, see
the topic
Hypothyroidism.

Treatment if the condition gets worse

After treatment with radioactive iodine, you may develop
hypothyroidism (too little thyroid hormone). Call your
doctor if you have any of the symptoms of hypothyroidism such as gaining
weight, feeling tired, or feeling cold more often than usual. If you do have
hypothyroidism, you may need to take
thyroid hormone medicine for the rest of your life.
For more information, see the topic
Hypothyroidism.

Prevention

Hyperthyroidism caused by Graves' disease is a genetic
disease that you cannot prevent.

People who smoke are more likely
to develop Graves' disease and Graves' ophthalmopathy than people who do not
smoke.

Home Treatment

Be sure to see your doctor
regularly so he or she can be sure that your
hyperthyroidism treatment is working, that you are
taking the right amount of medicine, and that you are not having any side
effects.

If you are taking antithyroid medicine, take it at the same time every day.

If you have
Graves' ophthalmopathy, you may need to use eyedrops
to help moisten your eyes and wear sunglasses to protect your eyes.

Medications

Antithyroid medicine is often used for
hyperthyroidism, because it works more quickly than
radioactive iodine therapy. Radioactive iodine therapy destroys part or all of the thyroid gland, depending on the dosage used. But antithyroid
medicine does not cause permanent thyroid damage.

You
may take antithyroid medicine before you have radioactive iodine treatment or
surgery—to bring your
metabolism to normal, to make you feel better, or to
reduce the chances of more serious problems.

Antithyroid medicine
does control hyperthyroidism in many people. But the medicine does have some
drawbacks.

You have to take the medicine for at least 1
year.

Your symptoms may come back after you stop taking it. And then you
have to start taking antithyroid medicine again or try a different
treatment.

There are some rare side effects from the medicine,
ranging from a rash to a low white blood cell count, which can make it hard for
your body to fight infection.

Your doctor may prescribe additional medicines
to treat symptoms caused by hyperthyroidism, such as rapid heartbeat or dry
eyes. These medicines can help you feel better while you wait for another
treatment to begin to work.

What to think about

Antithyroid medicine may or may not make your
hyperthyroidism permanently go away. The medicine is much more effective in people with mild disease. Up to 30 out of 100 people in the United States will have their hyperthyroidism go away (go into
remission) after taking antithyroid medicine for 12 to 18 months.3

Antithyroid medicine works
best if you have mild hyperthyroidism, if this is the first time you are being
treated for
Graves' disease, if you are younger than 50, or if
your
thyroid gland is only swollen a little bit (small
goiter). It is not used for
thyroiditis.

Antithyroid medicine is used
instead of radioactive iodine if you are pregnant, breast-feeding, or trying to
become pregnant.

Children are treated with antithyroid medicine, because experts
do not know if radioactive iodine treatment is safe for children. Treating
children with antithyroid medicine is challenging. It is hard to know
how much medicine they need when they are growing so quickly.

Your
doctor may prescribe low doses of thyroid hormone medicine to take with your
antithyroid medicine so that your thyroid hormone levels do not get too
low.

Surgery is the fastest
way to treat your hyperthyroidism. But it is not used very often and is more
risky than other treatments.

Other Treatment

Radioactive iodine is considered by many doctors to be the
best treatment for
hyperthyroidism. You swallow it in a liquid form or capsule, and
the iodine is taken up by your thyroid gland. The radioactivity in the iodine kills
most or all of the tissue in your thyroid gland. But it does not harm any other
parts of your body.

What to think about

Most people are cured of
hyperthyroidism after one dose of radioactive iodine.

The main
drawback of radioactive iodine is that it can damage your thyroid gland so that
your body no longer produces enough thyroid hormone. This is a common result of
treatment. And most people who receive radioactive iodine eventually develop
hypothyroidism (having too little thyroid hormone). If you develop hypothyroidism,
you will need to take
thyroid hormone medicine for the rest of your life.
For more information, see the topic
Hypothyroidism.

Radioactive iodine should
not be used by children or by women who are pregnant, women who are
breast-feeding, or women who want to become pregnant within 6 months of
treatment.

Doctors have used radioactive iodine to treat
hyperthyroidism for more than 60 years. There is no evidence that radioactive
iodine causes cancer, infertility, or birth defects.

Organizations

The American Thyroid Association promotes scientific and public
understanding of thyroid disorders. It publishes a monthly journal and manages
a Web site.

Hormone Health Network

8401 Connecticut Avenue

Suite 900

Chevy Chase, MD 20815-5817

Phone:

1-800-HORMONE (1-800-467-6663)

Web Address:

www.hormone.org

The Hormone Health Network is a nonprofit organization
started by the Endocrine Society. The organization promotes the prevention,
treatment, and cure of hormone-related conditions through public outreach and
education.

Bahn RS, et al. (2011). Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.
Thyroid, 21(6): 593–646. Also available online: http://www.liebertonline.com/doi/full/10.1089/thy.2010.0417.

Other Works Consulted

Bahn RS, et al. (2011). Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.
Thyroid, 21(6): 593–646. Also available online: http://www.liebertonline.com/doi/full/10.1089/thy.2010.0417.

Bahn RS, et al. (2011). Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists.
Thyroid, 21(6): 593–646. Also available online: http://www.liebertonline.com/doi/full/10.1089/thy.2010.0417.

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